Rebecca by Daphne DuMaurier (I got sucked into this book)
Neverwhere by Neil Gaiman
Nights at the Circus by Angela Carter
Memoirs of a Geisha by Arthur Golden
Jonathan Strange and Mr Norrell by Susanna Clarke

...I'll think of more later, maybe.

Love the authors on this list and especially love Angela Carter, although The Bloody Chamber is my favorite of hers, probably followed by Love.

Those are just a random few, as I have too much of a collection in my study.

And I love this list as well, but I'm biased because I've read most of them and enjoyed them all. Haven't read The Night Angel Trilogy but it sounds really good. You must have an awesome library.

This kind of thread is always so nice because I get ideas of what to read from other folks, but it's hard because it's more like the 10,001 books that "must" be read and 9, 900 remaining that I have yet to get to, with time being the rate-limiting factor. And I'm a slow reader. Anyway, my random list is skewed toward American and European books because that's mostly what I've read, and it might include:

The Bible
Any complete Shakespeare
Any complete Grimm's Fairy TalesOedipus Rex, Sophocles
These four make great reading on their own, but they also make interpreting other works and numerous cultural references easier.

A Wrinkle In Time, Madeleine L'EngleBeing and Nothingness, Jean-Paul SartreDivine Comedy, DanteDracula, Bram StokerEast of Eden, John Steinbeck (his whole collection, actually)Le Morte d'Arthur, Sir Thomas MalloryLove In the Time of Cholera, Gabriel Garcia MarquezNeuromancer, William GibsonOn the Origin of Species, Charles DarwinSongs of Innocence and Experience, William BlakeStranger In a Strange Land, Robert A. HeinleinThe Art of War, Sun TzuThe Chronicles of Narnia, C.S. LewisThe Foundation Trilogy, Isaac AsimovThe Left Hand of Darkness, Ursula Le Guin (and her other stuff)The Hobbit and The Lord of the Rings, J.R. R. TolkienThe Stranger, Albert CamusThe Tale of Genji, Murasaki ShikibuWar and Peace, Leo Tolstoy

And I agree that the required middle and high school literature is actually really good. Others have already mentioned these so I won't get into it here. There are some authors where I can't list individual works because their whole oeuvre is amazing and constitutes self-imposed "must read:" H.P. Lovecraft, Angela Carter, Italo Calvino, Charles Dickens, Edgar Allen Poe, E. M. Forster, Sigmund Freud, Neil Jordan, Ernest Hemingway, Hunter S. Thompson, Nathaniel Hawthorne, Carson McCullers, Charles Bukowski, Maurice Sendak, William Carlos Williams, Jane Austen, all the Brontes, Aldous Huxley, D.H. Lawrence, Fyodor Dostoyevsky, Joyce Carol Oates, Margaret Atwood, Neal Stephenson, Neil Gaiman...oh, it's endless so I'll stop. And I can't even get started on the poets.

And yes, I have these things right alongside my smut, Spawn comics, and manga. Even the don't-know-when-I'm-gonna-read Twilight box set that someone got for me because they thought if I like Dracula and "The Lady of the House of Love" from The Bloody Chamber, then I must be dying to read Twilight. Maybe someday.